{"id":"https://openalex.org/W2337267853","doi":"https://doi.org/10.1016/0890-5401(92)90019-c","title":"Extensional PERs","display_name":"Extensional PERs","publication_year":1992,"publication_date":"1992-06-01","ids":{"openalex":"https://openalex.org/W2337267853","doi":"https://doi.org/10.1016/0890-5401(92)90019-c","mag":"2337267853"},"language":"en","primary_location":{"id":"doi:10.1016/0890-5401(92)90019-c","is_oa":false,"landing_page_url":"https://doi.org/10.1016/0890-5401(92)90019-c","pdf_url":null,"source":{"id":"https://openalex.org/S59933527","display_name":"Information and Computation","issn_l":"0890-5401","issn":["0890-5401","1090-2651"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320990","host_organization_name":"Elsevier BV","host_organization_lineage":["https://openalex.org/P4310320990"],"host_organization_lineage_names":["Elsevier BV"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Information and Computation","raw_type":"journal-article"},"type":"article","indexed_in":["crossref"],"open_access":{"is_oa":false,"oa_status":"closed","oa_url":null,"any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5039178395","display_name":"Peter Freyd","orcid":null},"institutions":[{"id":"https://openalex.org/I79576946","display_name":"University of Pennsylvania","ror":"https://ror.org/00b30xv10","country_code":"US","type":"education","lineage":["https://openalex.org/I79576946"]}],"countries":["US"],"is_corresponding":false,"raw_author_name":"P. Freyd","raw_affiliation_strings":["University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA","institution_ids":["https://openalex.org/I79576946"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5112098993","display_name":"P. S. Mulry","orcid":null},"institutions":[{"id":"https://openalex.org/I39660569","display_name":"Colgate University","ror":"https://ror.org/05d23ve83","country_code":"US","type":"education","lineage":["https://openalex.org/I39660569"]}],"countries":["US"],"is_corresponding":false,"raw_author_name":"P. Mulry","raw_affiliation_strings":["Colgate University, Hamilton, New York 13346 USA"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Colgate University, Hamilton, New York 13346 USA","institution_ids":["https://openalex.org/I39660569"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5018870535","display_name":"Giuseppe Rosolini","orcid":"https://orcid.org/0000-0003-1672-9368"},"institutions":[{"id":"https://openalex.org/I124601658","display_name":"University of Parma","ror":"https://ror.org/02k7wn190","country_code":"IT","type":"education","lineage":["https://openalex.org/I124601658"]}],"countries":["IT"],"is_corresponding":false,"raw_author_name":"G. Rosolini","raw_affiliation_strings":["Universita degli Studi, 43100 Parma, Italy"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Universita degli Studi, 43100 Parma, Italy","institution_ids":["https://openalex.org/I124601658"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5109534784","display_name":"D. Scott","orcid":null},"institutions":[{"id":"https://openalex.org/I74973139","display_name":"Carnegie Mellon University","ror":"https://ror.org/05x2bcf33","country_code":"US","type":"education","lineage":["https://openalex.org/I74973139"]}],"countries":["US"],"is_corresponding":false,"raw_author_name":"D. Scott","raw_affiliation_strings":["Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 USA"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 USA","institution_ids":["https://openalex.org/I74973139"]}]}],"institutions":[],"countries_distinct_count":2,"institutions_distinct_count":4,"corresponding_author_ids":[],"corresponding_institution_ids":[],"apc_list":{"value":2630,"currency":"USD","value_usd":2630},"apc_paid":null,"fwci":7.2581,"has_fulltext":false,"cited_by_count":52,"citation_normalized_percentile":{"value":0.97000782,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":90,"max":95},"biblio":{"volume":"98","issue":"2","first_page":"211","last_page":"227"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10126","display_name":"Logic, programming, and type systems","score":0.9526000022888184,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T10126","display_name":"Logic, programming, and type systems","score":0.9526000022888184,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11010","display_name":"Logic, Reasoning, and Knowledge","score":0.9081000089645386,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/realizability","display_name":"Realizability","score":0.8325275182723999},{"id":"https://openalex.org/keywords/cartesian-closed-category","display_name":"Cartesian closed category","score":0.8187370300292969},{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.7679969072341919},{"id":"https://openalex.org/keywords/functor","display_name":"Functor","score":0.7446247935295105},{"id":"https://openalex.org/keywords/subcategory","display_name":"Subcategory","score":0.7248626351356506},{"id":"https://openalex.org/keywords/endomorphism","display_name":"Endomorphism","score":0.6462395787239075},{"id":"https://openalex.org/keywords/pure-mathematics","display_name":"Pure mathematics","score":0.582025945186615},{"id":"https://openalex.org/keywords/invariant","display_name":"Invariant (physics)","score":0.49045369029045105},{"id":"https://openalex.org/keywords/fixed-point","display_name":"Fixed point","score":0.4254833161830902},{"id":"https://openalex.org/keywords/algebra-over-a-field","display_name":"Algebra over a field","score":0.37338459491729736},{"id":"https://openalex.org/keywords/discrete-mathematics","display_name":"Discrete mathematics","score":0.3495591878890991},{"id":"https://openalex.org/keywords/mathematical-analysis","display_name":"Mathematical analysis","score":0.1433006227016449},{"id":"https://openalex.org/keywords/algorithm","display_name":"Algorithm","score":0.09532731771469116}],"concepts":[{"id":"https://openalex.org/C2776378722","wikidata":"https://www.wikidata.org/wiki/Q3454417","display_name":"Realizability","level":2,"score":0.8325275182723999},{"id":"https://openalex.org/C171032842","wikidata":"https://www.wikidata.org/wiki/Q1725874","display_name":"Cartesian closed category","level":2,"score":0.8187370300292969},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.7679969072341919},{"id":"https://openalex.org/C156772000","wikidata":"https://www.wikidata.org/wiki/Q864475","display_name":"Functor","level":2,"score":0.7446247935295105},{"id":"https://openalex.org/C2780617661","wikidata":"https://www.wikidata.org/wiki/Q541563","display_name":"Subcategory","level":2,"score":0.7248626351356506},{"id":"https://openalex.org/C116858840","wikidata":"https://www.wikidata.org/wiki/Q1340800","display_name":"Endomorphism","level":2,"score":0.6462395787239075},{"id":"https://openalex.org/C202444582","wikidata":"https://www.wikidata.org/wiki/Q837863","display_name":"Pure mathematics","level":1,"score":0.582025945186615},{"id":"https://openalex.org/C190470478","wikidata":"https://www.wikidata.org/wiki/Q2370229","display_name":"Invariant (physics)","level":2,"score":0.49045369029045105},{"id":"https://openalex.org/C61445026","wikidata":"https://www.wikidata.org/wiki/Q217608","display_name":"Fixed point","level":2,"score":0.4254833161830902},{"id":"https://openalex.org/C136119220","wikidata":"https://www.wikidata.org/wiki/Q1000660","display_name":"Algebra over a field","level":2,"score":0.37338459491729736},{"id":"https://openalex.org/C118615104","wikidata":"https://www.wikidata.org/wiki/Q121416","display_name":"Discrete mathematics","level":1,"score":0.3495591878890991},{"id":"https://openalex.org/C134306372","wikidata":"https://www.wikidata.org/wiki/Q7754","display_name":"Mathematical analysis","level":1,"score":0.1433006227016449},{"id":"https://openalex.org/C11413529","wikidata":"https://www.wikidata.org/wiki/Q8366","display_name":"Algorithm","level":1,"score":0.09532731771469116},{"id":"https://openalex.org/C37914503","wikidata":"https://www.wikidata.org/wiki/Q156495","display_name":"Mathematical physics","level":1,"score":0.0}],"mesh":[],"locations_count":2,"locations":[{"id":"doi:10.1016/0890-5401(92)90019-c","is_oa":false,"landing_page_url":"https://doi.org/10.1016/0890-5401(92)90019-c","pdf_url":null,"source":{"id":"https://openalex.org/S59933527","display_name":"Information and Computation","issn_l":"0890-5401","issn":["0890-5401","1090-2651"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320990","host_organization_name":"Elsevier BV","host_organization_lineage":["https://openalex.org/P4310320990"],"host_organization_lineage_names":["Elsevier BV"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Information and Computation","raw_type":"journal-article"},{"id":"pmh:oai:iris.unige.it:11567/294136","is_oa":false,"landing_page_url":"http://hdl.handle.net/11567/294136","pdf_url":null,"source":{"id":"https://openalex.org/S4377196291","display_name":"CINECA IRIS Institutial Research Information System (University of Genoa)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I83816512","host_organization_name":"University of Genoa","host_organization_lineage":["https://openalex.org/I83816512"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"info:eu-repo/semantics/article"}],"best_oa_location":null,"sustainable_development_goals":[{"score":0.41999998688697815,"display_name":"Reduced inequalities","id":"https://metadata.un.org/sdg/10"}],"awards":[],"funders":[],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":12,"referenced_works":["https://openalex.org/W79336753","https://openalex.org/W2007681226","https://openalex.org/W2079028772","https://openalex.org/W2094410575","https://openalex.org/W2121306658","https://openalex.org/W2161023112","https://openalex.org/W2168025539","https://openalex.org/W2291208220","https://openalex.org/W6678167238","https://openalex.org/W6684607093","https://openalex.org/W6696956747","https://openalex.org/W7046489447"],"related_works":["https://openalex.org/W2744653121","https://openalex.org/W2372920785","https://openalex.org/W2550443614","https://openalex.org/W4243341749","https://openalex.org/W3127570819","https://openalex.org/W1847007730","https://openalex.org/W2034974328","https://openalex.org/W4295745108","https://openalex.org/W3123970169","https://openalex.org/W2391207294"],"abstract_inverted_index":null,"counts_by_year":[{"year":2025,"cited_by_count":1},{"year":2023,"cited_by_count":1}],"updated_date":"2026-06-11T09:08:48.828518","created_date":"2016-06-24T00:00:00"}